Adaptive array wireless communication apparatus, reception level display method, reception level adjusting method, reception level display program and reception level adjusting program

ABSTRACT

In an adaptive array terminal, at least one of two antennas (ANT# 1 , ANT# 2 ) is a movable antenna. A display unit ( 6 ) of the terminal displays reception levels of, or level difference between, the two antennas. Thus, it becomes possible for a user to adjust an angle of the antenna such that reception levels of the two antennas come closer to the same level. Alternatively, a control unit ( 8 ) of the terminal automatically adjusts the antenna angle so that reception level difference between the two antennas becomes not higher than a prescribed value.

This Application is a Divisional of U.S. patent application Ser. No.10/528,097, filed Mar. 16, 2005, which is a National Phase Applicationof PCT/JP03/11179, filed Sep. 1, 2003, which claims priority fromJapanese Patent Application No. 2002-274409, filed Sep. 20, 2002. Theentire contents of the aforementioned applications are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to an adaptive array wirelesscommunication apparatus, a reception level display method, a receptionlevel adjusting method, a reception level display program and areception level adjusting program. Particularly, the present inventionrelates to a mobile terminal apparatus having an adaptive array functionusing a plurality of antennas, and to a reception level display method,a reception level adjusting method, a reception level display programand a reception level adjusting program used in such a mobile terminalapparatus.

BACKGROUND ART

Conventionally, in a mobile communication system such as a PHS (PersonalHandyphone System), wireless communication is established between amobile terminal apparatus (hereinafter referred to as a terminal) andwireless base station (hereinafter referred to as a base station).

A conventional terminal typically has one antenna, and a radio frequency(RF) signal received by the antenna is subjected to various signalprocessing including amplification and frequency conversion in an RFreceiving circuit.

One such signal processing performed in the RF receiving circuit ismeasurement of a reception power level (hereinafter referred to as areception level) of the received signal. The reception level of thesignal received by the antenna measured by the RF receiving circuit isdisplayed (notified) to the user on a display of the terminal, andhence, the user can estimate radio wave environment of the terminal.

A diversity terminal having two antennas and corresponding RF receivingcircuits and selecting one of the antennas that has higher receptionlevel as a reception antenna has been realized and disclosed, forexample, in Japanese Patent Laying-Open No. 8-97759.

The diversity terminal has two antennas as mentioned above, and areceived signal of one stream from either one of the antennas isselected, taken in the terminal and subjected to a signal processing fordemodulation. Therefore, only the reception level of the received signalof one stream selected for demodulation is displayed for the user.

As for the base station, an adaptive array base station has beenpractically implemented, at which a signal from a specific user isreceived by a plurality of antennas, and the received signals of theplurality of streams are subjected to well-known adaptive arrayprocessing, so that the received signal from the user is separated andextracted.

Here, the adaptive array processing refers to a well-known process inwhich based on received signals from terminals, a weight vectorconsisting of reception coefficients (weights) of respective ones of theplurality of antennas of the base station is estimated and adaptivelycontrolled, so that a signal from a specific terminal can be extracted(synthesized) accurately. As the adaptive array processing is wellknown, detailed description will not be given here.

As for the terminal, an adaptive array terminal having the function ofadaptive array processing has also been developed. Such an adaptivearray terminal has a plurality of (for example, two) antennas andcorresponding plurality of (two) RF receiving circuits, and signals of aplurality of streams received by respective antennas are taken into theterminal and subjected to the adaptive array processing.

As a characteristic of the adaptive array processing, it has been knownthat better reception characteristic can be attained when receptionlevel difference among the plurality of antennas is smaller. Actually,however, there is reception level difference generated among theplurality of antennas, because of difference in angle of the pluralityof antennas as well as fading.

In view of the foregoing, it is desired that the reception leveldifference among the plurality of antennas is adjusted by some method,in order to improve reception performance of the adaptive arrayterminal.

A terminal having two antennas, as is the case of the diversity terminaldescribed above, one of which is a fixed antenna provided inside theterminal and the other is a movable antenna mounted on the outside ofthe terminal of which angle can be adjusted by moving itself forward orbackward, has been implemented as an example of the conventionalterminals.

Conventionally, however, the reception level display for the user isonly the reception level of the signal of one stream received and takenin the terminal as described above, regardless of the number of antennasof the terminal.

Therefore, though the conventional terminal having a plurality of (two)antennas employs a movable antenna allowing angle adjustment of theantenna, it has been impossible to know the reception level of each ofthe plurality of antennas.

Therefore, similarly in the adaptive array terminal having a pluralityof antennas, it has been impossible for the user to know the receptionlevel of each antenna, and therefore, even if there is a movableantenna, it has been impossible for the user to adjust the angle of theantenna to make smaller the reception level difference among thereception antennas.

Further, in the conventional terminal having a plurality of antennasemploying a movable antenna, the reception level has been adjusted bythe user manually adjusting the angle of the movable antenna whilevisually monitoring the reception level displayed on the terminal, whichadjustment has been unsatisfactory in accuracy.

DISCLOSURE OF THE INVENTION

Therefore, an object of the present invention is to provide an adaptivearray wireless communication apparatus, a reception level displaymethod, a reception level adjusting method, a reception level displayprogram and a reception level adjusting program, by which it becomespossible for the user to readily adjust the reception level of theantenna even in an adaptive array wireless communication apparatushaving a plurality of antennas.

Another object of the present invention is to provide an adaptive arraywireless communication apparatus, a reception level display method, areception level adjusting method, a reception level display program anda reception level adjusting program, by which the reception level of theantenna can automatically be adjusted with high accuracy even in anadaptive array wireless communication apparatus having a plurality ofantennas.

According to one aspect, the present invention provides an adaptivearray wireless communication apparatus having a plurality of antennas,including determining means, display means and reception level adjustingmeans. The determining means determines reception levels of signals of aplurality of streams received by respective ones of the plurality ofantennas. The display means displays the determined reception levels ofthe signals of the plurality of streams. The reception level adjustingmeans allows, by manual operation by the user, adjustment of thereception levels of signals of the plurality of streams.

Preferably, the display means displays a numerical value indicative ofthe reception level of each of the signals of the plurality of streams.

Preferably, the display means displays a difference value between eachof the reception levels of the signals of the plurality of streams.

Preferably, the display means displays a degree of magnitude of thedifference value between each of the reception levels of the signals ofthe plurality of streams.

Preferably, the display means is capable of selectively displaying, ascontents of display, any of numerical value indicative of the receptionlevel of each of the signals of the plurality of streams, the differencevalue between each of the reception levels and a degree of magnitude ofthe difference value, and the adaptive array wireless communicationapparatus further includes display contents determining means fordetermining the contents to be displayed by the displaying means, inaccordance with prior designation by the user.

Preferably, the display means is capable of selectively displaying, ascontents of display, any of numerical value indicative of the receptionlevel of each of the signals of the plurality of streams, the differencevalue between each of the reception levels and a degree of magnitude ofthe difference value, and the adaptive array wireless communicationapparatus further includes display contents switching means forperiodically and successively switching the contents to be displayed bythe display means.

Preferably, the adaptive array wireless communication apparatus furtherincludes activating means for automatically activating the determiningmeans and the display means.

Preferably, the adaptive array wireless communication apparatus furtherincludes activating means for activating, in response to a userinstruction, the determining means and the reception level adjustingmeans.

According to another aspect, the present invention provides an adaptivearray wireless communication apparatus having a plurality of antennasincluding determining means, reception level difference calculatingmeans, and reception level adjusting means. The determining meansdetermines reception levels of signals of a plurality of streamsreceived by respective ones of the plurality of antennas. The receptionlevel difference calculating means calculates a difference among thedetermined reception levels of the signals of the plurality of streams.The reception level adjusting means adjusts the reception levels ofsignals of the plurality of streams such that the calculated receptionlevel difference decreases.

Preferably, the reception level adjusting means includes antenna drivingmeans for changing an angle between each of the plurality of antennas,and control means for controlling the antenna driving means such thatthe angle between each of the plurality of antennas is changed such thatthe reception level difference is not higher than a prescribed thresholdvalue.

Preferably, the adaptive array wireless communication apparatus furtherincludes activating means for automatically activating the determiningmeans and the reception level adjusting means.

Preferably, the adaptive array wireless communication apparatus furtherincludes activating means for activating, in response to a userinstruction, the determining means and the reception level adjustingmeans.

According to a further aspect, the present invention provides a methodof displaying a reception level in an adaptive array wirelesscommunication apparatus having a plurality of antennas, including thestep of determining reception levels of signals of a plurality ofstreams received by respective ones of the plurality of antennas, andthe step of displaying the determined reception levels of signals of theplurality of streams.

Preferably, in the display step, a numerical value indicative of thereception level of each of the signals of the plurality of streams isdisplayed.

Preferably, in the display step, a difference value between each of thereception levels of the signals of the plurality of streams isdisplayed.

Preferably, in the display step, a degree of magnitude of the differencevalue between each of the reception levels of the signals of theplurality of streams is displayed.

Preferably, in the display step, any of a numerical value indicative ofthe reception level of each of the signals of the plurality of streams,the difference value between each of the reception levels and a degreeof magnitude of the difference value can selectively be displayed as thedisplay contents, and the method of displaying the reception levelfurther includes the step of determining the contents to be displayed inthe display step in accordance with prior designation by the user.

Preferably, in the display step, any of a numerical value indicative ofthe reception level of each of the signals of the plurality of streams,the difference value between each of the reception levels and a degreeof magnitude of the difference value can selectively be displayed as thedisplay contents, and the method of displaying the reception levelfurther includes the step of periodically and successively switching thecontents to be displayed in the display step.

Preferably, the method of displaying the reception level furtherincludes the step of automatically activating the determining step andthe display step.

Preferably, the method of displaying the reception level furtherincludes the step of activating, in response to a user instruction, thedetermining step and the display step.

According to a still further aspect, the present invention provides amethod of adjusting a reception level in an adaptive array wirelesscommunication apparatus having a plurality of antennas including thestep of determining reception levels of signals of a plurality ofstreams received by respective ones of the plurality of antennas, thestep of calculating a difference among the determined reception levelsof the signals of the plurality of streams, and the step of adjustingthe reception levels of signals of the plurality of streams such thatthe calculated reception level difference decreases.

Preferably, the reception level adjusting step includes the step ofchanging an angle between each of the plurality of antennas such thatthe reception level difference is not higher than a prescribed thresholdvalue.

Preferably, the method of adjusting reception level further includes thestep of automatically activating the determining step and the receptionlevel adjusting step.

Preferably, the method of adjusting reception level further includes thestep of activating, in response to a user instruction, the determiningstep and the reception level adjusting step.

According to a still further aspect, the present invention provides areception level display program in an adaptive array wirelesscommunication apparatus having a plurality of antennas, causing acomputer to execute the step of determining reception levels of signalsof a plurality of streams received by respective ones of the pluralityof antennas, and the display step of displaying the determined receptionlevels of signals of the plurality of streams.

Preferably, in the display step, a numerical value indicative of thereception level of each of the signals of the plurality of streams isdisplayed.

Preferably, in the display step, a difference value between each of thereception levels of the signals of the plurality of streams isdisplayed.

Preferably, in the display step, a degree of magnitude of the differencevalue between each of the reception levels of the signals of theplurality of streams is displayed.

Preferably, in the display step, any of a numerical value indicative ofthe reception level of each of the signals of the plurality of streams,the difference value between each of the reception levels and a degreeof magnitude of the difference value can selectively be displayed as thedisplay contents, and the reception level display program causes thecomputer to further execute the step of determining the contents to bedisplayed in the display step, in accordance with prior designation bythe user.

Preferably, in the display step, any of a numerical value indicative ofthe reception level of each of the signals of the plurality of streams,the difference value between each of the reception levels and the degreeof magnitude of the difference value can selectively be displayed as thedisplay contents, and the reception level display program causes thecomputer to further execute the step of periodically and successivelyswitching the contents to be displayed in the display step.

Preferably, the reception level display program causes the computer tofurther execute the step of automatically activating the determiningstep and the display step.

Preferably, the program causes the computer to further execute the stepof activating, in response to a user instruction, the determining stepand the display step.

According to a further aspect, the present invention provides areception level adjusting program in an adaptive array wirelesscommunication apparatus having a plurality of antennas, causing acomputer to execute the step of determining reception levels of signalsof a plurality of streams received by respective ones of the pluralityof antennas, the step of calculating a difference value between each ofthe determined reception levels of the signals of the plurality ofstreams, and the step of adjusting the reception levels of signals ofthe plurality of streams such that the calculated reception leveldifference becomes smaller.

Preferably, the reception level adjusting step includes the step ofchanging an angle between each of the plurality of antennas such thatthe reception level difference is not higher than a prescribed thresholdvalue.

Preferably, the reception level adjusting program causes the computer tofurther execute the step of automatically activating the determiningstep and the reception level adjusting step.

Preferably, the reception level adjusting program causes the computer tofurther execute the step of activating, in response to a userinstruction, the determining step and the reception level adjustingstep.

Therefore, according to the present invention, in an adaptive arraywireless communication apparatus having a plurality of antennas, thereception levels of signals of a plurality of streams received byrespective ones of the plurality of antennas can be displayed to theuser. Therefore, it becomes possible for the user to adjust receptionlevel such that reception level difference among antennas decreases byadjusting, for example, an angle of a movable antenna while visuallymonitoring the display. Thus, the reception performance of adaptivearray processing in the adaptive array wireless communication apparatuscan further be improved.

Further, according to the present invention, in an adaptive arraywireless communication apparatus having a plurality of antennas,reception level difference of signals of the plurality of streamsreceived by respective ones of the plurality of antennas is calculated,and by automatically adjusting an angle of a movable antenna, forexample, to reduce the difference, the reception level can be adjustedwith higher accuracy. Therefore, the reception performance of adaptivearray processing in the adaptive array wireless communication apparatuscan further be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram representing a configuration of anadaptive array terminal in accordance with a first embodiment of thepresent invention.

FIG. 2 is a schematic diagram representing an exemplary method ofdisplaying the reception level of the adaptive array terminal inaccordance with a first embodiment of the present invention.

FIG. 3 is a flow chart representing an operation of the adaptive arrayterminal in accordance with the first embodiment of the presentinvention.

FIG. 4 is a functional block diagram representing a configuration of anadaptive array terminal in accordance with a second embodiment of thepresent invention.

FIG. 5 is a flow chart representing an operation of the adaptive arrayterminal in accordance with the second embodiment of the presentinvention.

BEST MODES FOR CARRYING OUT THE INVENTION

In the following, embodiments of the present invention will be describedin detail with reference to the figures. In the figures, the same orcorresponding portions will be denoted by the same reference charactersand description thereof will not be repeated.

First Embodiment

FIG. 1 is a functional block diagram representing a configuration of anadaptive array terminal in accordance with a first embodiment of thepresent invention.

A wireless downlink signal from a base station, not shown, is receivedby antennas ANT#1 and ANT#2, respectively, and applied as RF signals ofradio frequency to corresponding RF receiving circuits 1 and 2.

In each of RF receiving circuits 1 and 2, the received RF signal issubjected to prescribed analog processing such as amplification andfrequency conversion, and the resulting signal is applied to a signalprocessing unit 3. Under the control of a main control unit 5, signalprocessing unit 3 performs the adaptive array processing on the signalsreceived from RF receiving circuits 1 and 2, whereby desired receptionsignals are separated and extracted.

Specifically, in signal processing unit 3, a well-known adaptive arrayprocessing is performed, in which based on the reception signals fromthe base station, a weight vector consisting of weights of two antennasANT# 1 and ANT#2 of the terminal is estimated and adaptively controlled,so that the desired signal from the base station is extracted(synthesized) accurately.

The signal processing unit 3 shown in FIG. 1 includes a weight controlunit, not shown, for estimating the weight vector for each symbol of thereceived signal, and the weight control unit executes a process ofconverging the weight vector such that a square of a difference betweena complex multiplication sum of the received signal vector and theestimated weight vector and a known reference signal decreases, that is,the adaptive array processing of converging the reception directivityfrom the base station.

In the adaptive array processing, such a convergence of weight vector isperformed adaptively in accordance with time and variation ofpropagation path characteristics of signal waves, so that interferencecomponents and noise can be removed from the received signal and thesignal from the base station can be extracted.

In the weight control unit as such, sequential estimation algorithm suchas RLS (Recursive Least Squares) algorithm or LMS (Least Mean Square)algorithm is used.

RLS algorithm and LMS algorithm are well known in the field of adaptivearray processing and described in detail, for example, in AdaptiveSignal Processing by Array Antenna by Nobuyoshi Kikuma (Kagaku GijutsuShuppan), published on Nov. 25, 1998, “Chapter 3: MMSE Adaptive Array”on pp. 35-49 and, therefore, detailed description of adaptive arrayprocessing will not be given here.

Further, a demodulating unit 4 shown in FIG. 1 performs, under thecontrol by main control unit 5, a demodulating process on the receivedsignal separated and extracted by the adaptive array processing atsignal processing unit 3, and outputs demodulated bit outputs.

Main control unit 5 controls operations of not only the signalprocessing unit 3 and demodulating unit 4 described above but also of adisplay unit 6, which will be described later, in accordance with aninstruction by the user through an input unit 7.

In RF receiving circuits 1 and 2, reception levels of the receivedsignals are measured, and reception level 1 from RF receiving circuit 1and reception level 2 from RF receiving circuit 2, respectively, areapplied to main control unit 5.

Main control unit 5 converts reception levels 1 and 2 received from RFreceiving circuits 1 and 2 to various display formats, as will bedescribed later, and displays on display unit 6 at a prescribed timing.

Display unit 6 may be implemented by display devices of various types,such as light emitting diode (LED) and liquid crystal display (LCD).When implemented by an LED, for example, the reception level may beindicated by flickering or the color of light emission. When implementedby an LCD, the reception level may be indicated by characters ornumerical values appearing on the display screen.

FIG. 2 is a schematic diagram representing an exemplary method ofdisplaying the reception level of the adaptive array terminal inaccordance with a first embodiment of the present invention.

In FIG. 2, (a) schematically shows a frontal view of an adaptive arrayterminal 100. Referring to FIG. 2 (a), adaptive array terminal 100 hastwo antennas ANT#1 and ANT#2, at least one of which is a movable antennathat can be moved forward and backward, allowing adjustment of an anglewith the other antenna.

It is assumed that adaptive array terminal 100 has the display unitcorresponding to display unit 6 of FIG. 1 implemented by an LED and/orLCD. In the following, the manner of displaying the reception levelusing these display units will be described.

FIG. 2 (b) shows an exemplary Display Method 1 in accordance with thefirst embodiment of the present invention. In Display Method 1,reception levels of two antennas ANT#1 and ANT#2 are displayed directlyas numerical values based on reception levels 1 and 2 from RF receivingcircuits 1 and 2, on the display unit formed of LCD on adaptive arrayterminal 100, by an instruction from main control unit 5.

For instance, in the example of FIG. 2 (b), as the image on the displayunit formed of LCD, 30 dBμV as the reception level of antenna ANT#1 and32 dBμV as the reception level of antenna ANT#2 are displayed.

Visually monitoring the display, the user manually adjusts the angle ofmovable antenna so that the two antennas come to have the same receptionlevels.

Next, FIG. 2 (c) shows an exemplary Display Method 2 in accordance withthe first embodiment of the present invention. In Display Method 2,reception level difference between reception levels of two antennasANT#1 and ANT#2 is calculated by main control unit 5 based on receptionlevels 1 and 2 from RF receiving circuits 1 and 2, and is displayed as adifference value, on the display unit formed of an LCD on adaptive arrayterminal 100.

For instance, in the example of FIG. 2 (c), as the image on the displayunit formed of LCD, 2 dBμV is displayed as the difference value betweenthe reception level of antenna ANT#1 and the reception level of antennaANT#2.

Visually monitoring the display, the user manually adjusts the angle ofmovable antenna so that the reception level difference between the twoantennas becomes zero level.

Next, FIG. 2 (d) shows an exemplary Display Method 3 in accordance withthe first embodiment of the present invention. In Display Method 3,reception level difference between reception levels of two antennasANT#1 and ANT#2 is calculated by main control unit 5 based on receptionlevels 1 and 2 from RF receiving circuits 1 and 2, and is displayed as adegree of magnitude of difference value, on the display unit formed ofan LCD.

By way of example, such a degree of magnitude of difference value may bedetermined by main control unit 5, in which the magnitude of differencevalue is compared with a prescribed threshold value or values to beclassified into three, that is, large, medium and small.

In the example of FIG. 2 (d-1), as an image on the display unit formedof LCD, “small” is displayed as the degree of magnitude of differencevalue between the reception level of antenna ANT#1 and reception levelof antenna ANT#2.

In the example of FIG. 2 (d-2), as an image on the display unit formedof three LEDs, one LED corresponding to “small” as the degree ofmagnitude of difference value between the reception level of antennaANT#1 and reception level of antenna ANT#2 is turned on.

In the example of FIG. 2 (d-3), as an image on the display unit formedof one LED, the LED is turned on with flicker rate or with a colorcorresponding to “small” as the degree of magnitude of difference valuebetween the reception level of antenna ANT#1 and reception level ofantenna ANT#2.

For instance, if the degree of magnitude of difference value is “large”,the LED may be flickered at a high rate, if it is “middle”, the LED maybe flickered at a middle rate, and if it is “small”, the LED may be kepton without flickering.

Alternatively, if the degree of magnitude of difference value is“large”, red light may be emitted from the LED, if it is “middle”,yellow light may be emitted from the LED, and if it is “small”, greenlight may be emitted.

Visually monitoring the display, the user manually adjusts the angle ofmovable antenna so that the reception level difference between the twoantennas becomes smaller.

As for the selection of Display Methods 1 to 3 described above, the usermay designate the method by an operation through input unit 7beforehand, or Display Methods 1 to 3 may be periodically andsuccessively switched.

Further, the processes of determining and displaying reception leveldescribed above may be automatically activated by the adaptive arrayterminal, or may be activated triggered by the user operation throughinput unit 7.

The configuration of the functional block of the adaptive array terminalshown in FIG. 1 is actually realized by software executed by a digitalsignal processor (DSP), not shown, along the flow chart of FIG. 3. DSPreads a program including various steps of the flow chart of FIG. 3 froma memory, not shown, and executes the program. The program may beinstalled from the outside.

In the following, an operation of the adaptive array terminal inaccordance with the first embodiment of the present invention will bedescribed.

First, in step S1, an operation related to the display is automaticallyactivated by a timer interruption, or an operation related to thedisplay is automatically activated by an operation of the input unit bythe user.

In step S2, whether the display method (for example, any of DisplayMethods 1 to 3 described with reference to FIG. 2) has been designatedin advance by the user or not is determined.

When the method is not specifically designated, in step S3, a displaymethod next to the one used last time is used as the display method(specifically, in step S3, Display Methods 1 to 3 are displayedincremented successively).

In step S2, if it is determined that the display method has beendesignated beforehand, the flow proceeds to step S4, and whether thedesignated display method is Display Method 1 of FIG. 2 (b) or not isdetermined.

If it is determined in step S4 that the designated method is DisplayMethod 1, the flow proceeds to steps S5 in which reception level valuesof antennas ANT#1 and ANT#2 are displayed directly, in accordance withDisplay Method 1 as shown in FIG. 2 (b).

If it is determined in step S4 that the designated method is not DisplayMethod 1, the flow proceeds to step S6 in which whether the designateddisplay method is Display Method 2 of FIG. 2 (c) or not is determined.

If it is determined in step S6 that the designated method is DisplayMethod 2, the flow proceeds to steps S7 in which a difference valuebetween reception levels of antennas ANT#1 and ANT#2 is displayed, inaccordance with Display Method 2 as shown in FIG. 2 (c).

If it is determined in step S6 that the designated method is not DisplayMethod 2, the flow proceeds to step S8, in which the degree of magnitudeof difference value between reception levels of antennas ANT#1 and ANT#2is displayed, in accordance with Display Method 3 as shown in FIG. 2(d).

By the repetition of the above described processes, when the displaymethod has been designated by the user, the display is given in thedesignated display method, and otherwise, Display Methods 1 to 3 aresuccessively repeated.

As described above, according to the first embodiment of the presentinvention, in an adaptive array terminal having a plurality of antennas,reception levels of the signals of a plurality of streams received byrespective ones of the plurality of antennas can be displayed (notified)to the user in various manners. Therefore, it becomes possible for theuser to adjust the reception level such that reception level differenceamong antennas decreases by adjusting, for example, an angle of amovable antenna, that is, an angle of an antenna with another antenna,while visually monitoring the display. Thus, the reception performanceof adaptive array processing in the adaptive array wirelesscommunication apparatus can further be improved.

Second Embodiment

FIG. 4 is a functional block diagram representing a configuration of anadaptive array terminal in accordance with the second embodiment of thepresent invention. The functional block diagram of FIG. 4 is the same asthe functional block diagram of the first embodiment of FIG. 1 exceptfor the following points, and description of common portions will not berepeated.

Specifically, in the functional block diagram of FIG. 4, in place of (orin addition to) display unit 6 shown in FIG. 1, an antenna drive controlunit 8 is provided. Further, in place of main control unit 5 controllingdisplay unit 6 of FIG. 1, a main control unit 9 controlling antennadrive control unit 8 is provided.

Antenna drive control unit 8 automatically drives and controls the angleadjustment of the movable antenna, of which angle can be changed bymoving forward or backward, of the two antennas of the adaptive arrayterminals, in accordance with a control signal from main control unit 9.

Main control unit 9 calculates the reception level difference betweenreception levels 1 and 2 received from RF receiving circuits 1 and 2,and if it is determined that the level difference is not smaller than aprescribed threshold value, controls antenna drive control unit 8 suchthat the angle of the two antennas with each other is adjusted to makethe level difference not larger than the threshold value.

The processes of determining the reception level and antenna drivecontrol described above may be automatically activated by the adaptivearray terminal, or may be activated triggered by the user operationthrough input unit 7.

The configuration of the functional block of the adaptive array terminalshown in FIG. 4 is actually realized by software executed by a digitalsignal processor (DSP), not shown, along the flow chart of FIG. 5. DSPreads a program including various steps of the flow chart of FIG. 5 froma memory, not shown, and executes the program. The program may beinstalled from the outside.

In the following, an operation of the adaptive array terminal inaccordance with the second embodiment of the present invention will bedescribed with reference to FIG. 5. In the following description, it isassumed that two antennas provided on the adaptive array terminal areboth movable antennas of which angles can be changed.

First, in step S11, an operation related to the antenna control isautomatically activated by a timer interruption, or an operation relatedto the antenna control is automatically activated by an operation of theinput portion by the user.

Thereafter, in step S12, the reception level difference is calculatedfrom reception levels 1 and 2 corresponding to antennas ANT#1 and ANT#2.

Next, in step S13, whether the calculated reception level difference isnot lower than a prescribed threshold value or not is determined. If itis determined that the reception level difference is equal to or lowerthan the threshold value, the process is terminated.

If it is determined that the reception level difference is not lowerthan the prescribed threshold value, the angle of antenna ANT#1 ischanged and reception level 1 corresponding to each angle is obtainedand stored in step S14.

Next, in step S15, the angle of antenna ANT#2 is changed and receptionlevel 2 corresponding to each angle is obtained and stored.

Then, in step S16, the maximum value among the obtained reception levels1 and the maximum value among the obtained reception levels 2 areextracted, and the level difference therebetween is compared with aprescribed threshold value.

In step S17, if it is determined that the level difference is equal toor smaller than the threshold value, the flow proceeds to step S18, inwhich angles of antennas ANT#1 and ANT#2 are adjusted such that maximumvalues of reception levels 1 and 2 are attained.

In step S17, if it is determined that the level difference is not lowerthan the threshold value, maximum values of reception levels 1 and 2 ofantennas ANT#1 and ANT#2 are compared with each other, and whether thereception level of the antenna having the smaller maximum value is thesame as or lower than a prescribed threshold value or not is determined.

If it is determined that the value is the same or lower than thethreshold value, the flow proceeds to step S20, in which angels ofantennas ANT#1 and ANT#2 are adjusted so that reception levels 1 and 2both attain the maximum values. Then, the process is terminated.

The reason for this is as follows. If the reception level of the antennahaving smaller maximum value is equal to or smaller than the thresholdvalue and is too small, it is better to attain higher reception level ateach antenna even if there is considerable reception level difference,rather than to adjust the reception level using the antenna of such lowreception level as the reference.

In step S19, if the reception level of the antenna having smallermaximum value is not lower than the threshold value, that is, if it isnot too small, the angle of the antenna is adjusted such that thereception level of that antenna attains the maximum value, in step S21.

Next, in step S22, the angle of the antenna having larger maximum valueis adjusted such that the reception level difference from the antennahaving smaller maximum value is not higher than the threshold value andthe reception level attains the highest under this condition.

Thus, the highest possible reception level can be attained while thereception level difference between the two antennas is kept within thetolerable range.

As described above, in the second embodiment of the present invention,in an adaptive array terminal having a plurality of antennas, receptionlevel difference of signals of the plurality of streams received byrespective ones of the plurality of antennas is calculated, and byautomatically adjusting an angle of a movable antenna, for example, toreduce the difference, the reception level can be adjusted with higheraccuracy. Therefore, the reception performance of adaptive arrayprocessing in the adaptive array wireless communication apparatus canfurther be improved.

In the first and second embodiments described above, the number ofantennas of the adaptive array terminal is two. The number is notlimited to two, and it may be any number necessary for adaptive arrayprocessing. Further, it is not necessary that the plurality of antennasare all movable. Movable and unmovable antennas may exist in a mixedmanner, provided that the angle between each of the antennas can beadjusted.

As described above, according to the present invention, in an adaptivearray wireless communication apparatus having a plurality of antennas,it is possible to indicate the reception levels of signals received byrespective ones of the plurality of antennas. Therefore, it becomespossible for the user to adjust reception level such that receptionlevel difference among antennas decreases by adjusting, for example, anangle of a movable antenna while visually monitoring the display. Thus,the reception performance of adaptive array processing in the adaptivearray wireless communication apparatus can further be improved.

Further, according to the present invention, in an adaptive arraywireless communication apparatus having a plurality of antennas,reception level difference of signals of the plurality of systemsreceived by respective ones of the plurality of antennas is calculated,and by automatically adjusting an angle of a movable antenna, forexample, to reduce the difference, the reception level can be adjustedwith higher accuracy. Therefore, the reception performance of adaptivearray processing in the adaptive array wireless communication apparatuscan further be improved.

INDUSTRIAL APPLICABILITY

According to the present invention, reception levels of a plurality ofantennas are displayed to the user to make it possible for the user toadjust reception level, or, automatic adjustment of the reception levelis made possible to reduce the reception level difference. Therefore,the invention is effective in an adaptive array wireless communicationapparatus having a plurality of antennas.

1. An adaptive array wireless communication apparatus having a pluralityof antennas, comprising: determining unit that determines, beforeperforming adaptive array processing, reception levels of signals of aplurality of streams received by respective ones of said plurality ofantennas; reception level difference calculating unit that calculates adifference among said determined reception levels of signals of saidplurality of streams; and reception level adjusting unit that adjuststhe reception levels of signals of said plurality of streams such thatsaid calculated reception level difference decreases.
 2. A method ofadjusting a reception level in an adaptive array wireless communicationapparatus having a plurality of antennas, comprising the steps of:determining, before performing adaptive array processing, receptionlevels of signals of a plurality of streams received by respective onesof said plurality of antennas; calculating a difference among saiddetermined reception levels of signals of said plurality of streams; andadjusting the reception levels of signals of said plurality of streamssuch that said calculated reception level difference decreases.
 3. Areception level adjusting program in an adaptive array wirelesscommunication apparatus having a plurality of antennas, comprising: oneor more computer-readable media having computer-readable program codeembodied therein or among them if more than one computer-readablemedium, to be executed by a computer, the computer-readable program codefor performing the steps: determining, before performing adaptive arrayprocessing, reception levels of signals of a plurality of streamsreceived by respective ones of said plurality of antennas, calculating adifference value between each of said determined reception levels of thesignals of said plurality of streams, and adjusting the reception levelsof signals of said plurality of streams such that said calculatedreception level difference becomes smaller.
 4. The reception leveladjusting program according to claim 3, wherein said reception leveladjusting step includes the step of changing an angle between each ofsaid plurality of antennas such that the reception level difference isnot higher than a prescribed threshold value.
 5. The reception leveladjusting program according to claim 3, causing the computer to furtherexecute the step of automatically activating said determining step andsaid display step.
 6. The reception level adjusting program according toclaim 3, causing the computer to further execute the step of activatingsaid determining step and said display step in response to a userinstruction.